This invention relates in general to projection systems, and more particularly to a system for projecting an image on a surface having an exposed aperture therein while optically obscuring the aperture.
In most projecting systems, the projected image is cast upon a continuous surface of relatively high reflectivity. However, in some highly specialized systems, it is desirable to have an opening or aperture in the surface onto which the image is cast. This is particularly true in full or wide field-of-view projection systems.
For example, flight simulators for instructing and testing aircraft pilots utilize several projectors which cast images of simulated terrain and sky on a spherical surface or dome that is usually about 40 feet in diameter. Other projectors may cast images of nearby aircraft, clouds or targets. The simulated cockpit is at the center of the dome, and to reduce glare and impart a measure of reality to the simulated flight, all the projectors must be hidden from the student pilots field of vision. This presents little problem for those projectors used for the imagery directly ahead of the flight path, for those projectors may be located immediately in front of the cockpit. However, to broaden the field of view, it is either necessary to expose some of the projectors to the student pilot, in which case the realism is diminished and he subjected to glare, or else it is necessary to project through apertures in the surface of the dome, in which case the apertures stand out boldly in the projected scene.